Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
  • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
  • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
  • F04C18/344—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
  • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
  • F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids

Definitions

• the invention relates to a control device for positive displacement pumps, in particular vane pumps which have a pressure chamber which is connected to a pressure channel connected to an outlet via a bore in which a throttle piston can be displaced against the force of a spring.
• the throttle piston controls an outlet cross-section depending on the pump speed or the flow rate.
• a spring-loaded flow control piston is present in a housing bore, the front end face of which is connected to the pressure chamber.
• a rear end face of the flow control piston projects into a chamber which contains the outlet pressure downstream of the throttle device.
• the flow control piston releases a connection from the pressure chamber to a pump inlet channel depending on the differential pressure acting on the two end faces.
• Such a control device is known from DE 41 01 210-A1.
• the throttle piston moves with increasing speed due to a dynamic pressure acting on one end face.
• a control edge cuts a piston opening connected to a pressure chamber, so that the reducing cross-section of the passage means that less and less pressure oil can flow out to an outlet.
• This arrangement represents the throttle device.
• the differential pressure acting on the flow control piston increases so that it regulates an ever increasing flow rate to the pump inlet side. Since the controllable opening is in the throttle piston, the differential pressure also acts on the rear of the piston of the throttle device. In a basic position, the throttle piston closes off with its end face a passage connected to the pressure chamber or the interior, for which purpose a relatively stiff spring is required. This spring force must be overcome by the delivery pressure when the pump starts. For this reason, a significantly higher pump pressure must be built up in one pressure zone in a double-flow pump, so that the pump runs relatively loud because of the different pressures. In addition, the piston is designed as a stepped piston with a snug fit, which requires a certain amount of production.
• the invention has for its object to provide a control device for a falling flow rate characteristic with as little construction effort as possible, without significantly increasing the power consumption of the pump.
• the falling characteristic curve should also be independent of the opening travel and the differential pressure of the flow control piston in order to avoid a disturbance variable.
• the novel throttle device is designed in such a way that the pressure chamber in the area of the bore containing the throttle piston is continuously connected to a spring chamber via a bypass channel and the throttle piston controls the cross section of a throttle channel connecting the spring chamber to the outlet channel.
• bypass channel Pour into a bearing housing in a T-shape, the vertical duct section being open towards the bore.
• FIG. 1 shows a longitudinal section through a vane pump with the control device, in which the throttle piston and the flow control piston are in their basic position
• Fig. 2 is a partial cross section along the line II-II in Fig. 1 and
• FIG. 3 shows detail III of FIG. 1 on an enlarged scale.
• the vane pump is used to deliver pressure oil in a container (not shown) to a consumer (not shown), for example an auxiliary power steering system.
• a rotor set 3 is inserted in an oil-filled pressure chamber 1 of a housing 2.
• the rotor set 3 consists of a cam ring 4 and a rotor 5.
• the rotor 5 is arranged in the interior of the cam ring 4 and has radially directed slots in which vanes 6 can be displaced.
• Working chambers are formed between the cam ring, the rotor 5 and the vanes 6 and are delimited in the axial direction by control surfaces of adjacent control plates 7 and 8.
• the housing 2 is composed of a bearing housing 10 and a cup-shaped housing cover 11.
• the rotor 5 is mounted in the bearing housing 10 via a drive shaft 12.
• the bearing point in the bearing housing 10 is the only bearing of the drive shaft 12. This means that the drive shaft 12 is not supported in the housing cover 11 in the radial direction. Rather, the drive shaft is supported on the housing cover 11 in the axial direction.
• a flow control valve 13 is provided in the bearing housing 10 for regulating the pressure oil led to the pressure connection.
• the formation of the flow control valve 13 and a pressure relief valve, which is also still present and is not visible, is generally known, for example from US Pat. No. 5,098,259 and is therefore not described in more detail.
• the suction and pressure channels which connect the working chambers to the suction connection, the flow control valve 13 and the pressure relief valve are arranged in the bearing housing 10. These channels are also generally known and are therefore not described in detail.
• the control plate 7 has two openings 14 and 14A, which with the between Rotor 5, the cam ring 4 and the wings 6 formed pressure-carrying working chambers are connected.
• the delivery pressure prevails in pressure chamber 1.
• a piston bore 15 axially adjoins the upper opening 14.
• the piston bore 15 contains a throttle piston 17, on which a spring 16 inserted into a spring chamber 15A presses.
• the pressure chamber 1 is continuously connected via a bypass duct 18 via the spring chamber 15A and a throttle duct 20 controllable by the throttle piston 17 to an outlet duct 21 leading to the consumer.
• a chamfer 19 on the throttle piston 17 controls the throttling process.
• a suction channel 9 is connected to the oil container.
• the bypass channel 18, as can be seen from the cross section in FIG. 2, is cast into the bearing housing 10 in a T-shape and is open towards the piston bore 15 with its vertically extending channel section 18A. In each position of the throttle piston 17, the connection from the pressure chamber 1 to the outlet channel 21 is therefore maintained. The throttle piston 17 therefore does not require a snug fit.
• the spring 16 presses the throttle piston 17 against the control plate 7.
• the vanes 6 push the oil trapped between them through the openings 14 and 14A.
• the throttle piston 17 is displaced to the right by the dynamic pressure acting on its end face. The higher the flow rate through the opening 14, the further the throttle piston 17 moves against the force of the spring 16.
• the throttle piston 17 reduces the outflow through the throttle duct 20 to the outlet duct 21 more or less.
• the respective flow cross-section of the throttle duct 20, which specifies the delivery quantity of the pump available in the consumer, can be therefore change depending on the pump speed. The falling flow characteristic is obtained.
• control piston 22 acts as a pressure compensator and this shifts to the right against the force of a spring 23 and against the force of the outlet pressure prevailing in a chamber 24.
• the end face of the control piston 22 opens an inlet channel 25. A partial flow thus returns to the inlet side of the pump in a known manner.
• the throttle piston 17 is not influenced by the differential pressure of the control piston 22 with its spring 23, but is shifted by the flow of the one opening 14 via the bypass channel 18. This measure provides a continuous displacement path of the throttle piston 17 with a small spring force.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Details And Applications Of Rotary Liquid Pumps (AREA)
• Rotary Pumps (AREA)
• Details Of Reciprocating Pumps (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6528751

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (13)

Citations (3)

Family Cites Families (2)

• 1994
  • 1994-09-21 DE DE4433598A patent/DE4433598A1/de not_active Withdrawn
• 1995
  • 1995-09-15 BR BR9508971A patent/BR9508971A/pt not_active IP Right Cessation
  • 1995-09-15 JP JP8510574A patent/JPH10505889A/ja not_active Ceased
  • 1995-09-15 DE DE59504439T patent/DE59504439D1/de not_active Expired - Lifetime
  • 1995-09-15 KR KR1019970701386A patent/KR100344812B1/ko not_active IP Right Cessation
  • 1995-09-15 US US08/793,949 patent/US5810565A/en not_active Expired - Fee Related
  • 1995-09-15 WO PCT/EP1995/003629 patent/WO1996009475A1/de active IP Right Grant
  • 1995-09-15 EP EP95932754A patent/EP0782672B1/de not_active Expired - Lifetime
  • 1995-09-15 ES ES95932754T patent/ES2124589T3/es not_active Expired - Lifetime

Patent Citations (3)

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